scsi: megaraid_sas: enable intx only if msix request fails

Without this fix, driver will enable INTx Interrupt pin even though
MSI-x vectors are enabled. See below lspci output. DisINTx is unset for
MSIx setup.

lspci -s 85:00.0 -vvv |grep INT |grep Control
Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr-
Stepping- SERR+ FastB2B- DisINTx-

After applying this fix, driver will enable INTx Interrupt pin only if
Legacy interrupt method is required.  See below lspci output. DisINTx is
set for MSIx setup.  lspci -s 85:00.0 -vvv |grep INT |grep Control
Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr-
Stepping- SERR+ FastB2B- DisINTx+
Signed-off-by: Kashyap Desai <kashyap.desai@broadcom.com>
Reviewed-by: Tomas Henzl <thenzl@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/megaraid/megaraid_sas_base.c

@@ -5034,10 +5034,12 @@ megasas_setup_irqs_msix(struct megasas_instance *instance, u8 is_probe)
 					 &instance->irq_context[j]);
 			/* Retry irq register for IO_APIC*/
 			instance->msix_vectors = 0;
-			if (is_probe)
+			if (is_probe) {
+				pci_free_irq_vectors(instance->pdev);
 				return megasas_setup_irqs_ioapic(instance);
-			else
+			} else {
 				return -1;
+			}
 		}
 	}
 	return 0;
@@ -5277,9 +5279,11 @@ static int megasas_init_fw(struct megasas_instance *instance)
 			MPI2_REPLY_POST_HOST_INDEX_OFFSET);
 	}
 
-	i = pci_alloc_irq_vectors(instance->pdev, 1, 1, PCI_IRQ_LEGACY);
-	if (i < 0)
-		goto fail_setup_irqs;
+	if (!instance->msix_vectors) {
+		i = pci_alloc_irq_vectors(instance->pdev, 1, 1, PCI_IRQ_LEGACY);
+		if (i < 0)
+			goto fail_setup_irqs;
+	}
 
 	dev_info(&instance->pdev->dev,
 		"firmware supports msix\t: (%d)", fw_msix_count);